The influence of Widmanstätten ferrite, martensite and grain boundary carbides on the strength and impact behaviour of high Al (0.2%) and Nb containing hot rolled steels

The influence of Al and Nb on the strength and impact behaviour of hot rolled 0.06%C, 1.4%Mn steels has been determined after hot rolling to 15 and 30 mm thick plate. When 0.16%Al was added to the plain C-Mn steel, the impact behaviour significantly improved even though Widmanstätten ferrite (WF) was present. This improvement was due to refinement of the grain boundary carbides and removing the N from solution as AlN. The hot rolled steels all contained WF but when Nb was added more WF formed as well as MA giving poor impact behaviour. Reducing the hardenability from that shown in previous work by decreasing C from 0.1 to 0.06%, Nb from 0.03 to 0.02%, and cooling rate from 33 to 17 K/min had no effect in improving the impact performance of hot rolled Nb steels. To ensure optimum properties not only is it necessary to reduce the hardenability, but WF formation must be discouraged by having a high Ar3. This can only be presently achieved by refining the austenite grain size via control rolling the Nb containing steels; the benefit of adding Al can then, readily be seen. Suggestions are made as to how this might be achieved for hot rolling

Toward Defining Literacy

Literacy is a topic much on the public\u27s mind these days. It is one of those subjects on which all laypersons think they are experts. When it comes time, however, to establish measures of illiteracy rates or to set policies, it becomes apparent that we know less than we thought we did. It is small comfort to know that specialists also have their differences

Alvin titanium electrical penetrator design, manufacture, and testing : interim report

Under the U.S. Navy's Project TITANES a new titanium alloy pressure hull has been designed, built, and installed for use in the deep-submersible ALVIN. The Woods Hole Oceanographic Institution was assigned the task of designing, procuring and testing the through-hull electrical penetrators for the new sphere. This interim report traces the progress of this Woods Hole program from the initial design stage, through the various phases of manufacture and electrical testing, to the installation of the units in the completed hull, and the numerous laboratory~ pressure tank, and at-sea tests conducted to verify the satisfactory performance of the new penetrators. The results of all laboratory and in-service testing done to date support the conclusion that the performance of the titanium penetrators meets all of the original specifications.Office of Naval Research Contract No. NOr014-73-C-0097 NR 265-10

Examining the efficacy of six published time-lapse imaging embryo selection algorithms to predict implantation to demonstrate the need for the development of specific, in-house morphokinetic selection algorithms.

OBJECTIVE: To study the efficacy of six embryo-selection algorithms (ESAs) when applied to a large, exclusive set of known implantation embryos. DESIGN: Retrospective, observational analysis. SETTING: Fertility treatment center. PATIENT(S): Women undergoing a total of 884 in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment cycles (977 embryos) between September 2014 and September 2015 with embryos cultured using G-TL (Vitrolife) at 5% O2, 89% N2, 6% CO2, at 37°C in EmbryoScope instruments. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Efficacy of each ESA to predict implantation defined using specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), area under the receiver operating characteristic curve (AUC), and likelihood ratio (LR), with differences in implantation rates (IR) in the categories outlined by each ESA statistically analyzed (Fisher's exact and Kruskal-Wallis tests). RESULT(S): When applied to an exclusive cohort of known implantation embryos, the PPVs of each ESA were 42.57%, 41.52%, 44.28%, 38.91%, 38.29%, and 40.45%. The NPVs were 62.12%, 68.26%, 71.35%, 76.19%, 61.10%, and 64.14%. The sensitivity was 16.70%, 75.33%, 72.94%, 98.67%, 51.19%, and 62.33% and the specificity was 85.83%, 33.33%, 42.33%, 2.67%, 48.17%, and 42.33%, The AUC were 0.584, 0.558, 0.573, 0.612, 0.543, and 0.629. Two of the ESAs resulted in statistically significant differences in the embryo classifications in terms of IR. CONCLUSION(S): These results highlight the need for the development of in-house ESAs that are specific to the patient, treatment, and environment. These data suggest that currently available ESAs may not be clinically applicable and lose their diagnostic value when externally applied

Preliminary investigation of the prevalence and implantation potential of abnormal embryonic phenotypes assessed using time-lapse imaging.

This retrospective, single site observational study aimed to delineate five abnormal embryonic developmental phenotypes, assessing their prevalence, development potential and suitability for inclusion in embryo selection models for IVF. In total, 15,819 embryos from 4559 treatment cycles cultured in EmbryoScope® incubators between January 2014 and January 2016 were included. Time-lapse images were assessed retrospectively for five abnormal embryo phenotypes: direct cleavage, reverse cleavage, absent cleavage, chaotic cleavage and cell lysis. The prevalence of each abnormal phenotype was assessed. Final embryo disposition, embryo quality and implantation rate were determined and compared with a control embryo cohort. The collective prevalence for the five abnormal phenotypes was 11.4%; chaotic cleavage and direct cleavage together constituted 9.7%. Implantation rates were 17.4%, 0%, 25%, 2.1% and 0% for direct, reverse, absent, chaotic cleavage and cell lysis, respectively. The overall implantation rate for all abnormal embryos with known implantation status was significantly lower compared with the control population (6.9% versus 38.7%, P < 0.0001). The proportion of good quality embryos in each category of abnormal cleavage remained below 25%. Embryos exhibiting an abnormal phenotype may have reduced developmental capability, manifested in both embryo quality and implantation potential, when compared with embryos of normal phenotype

Relative Sea-Level Change in the Northern Strait of Georgia, British Columbia

Twenty-four new radiocarbon dates from isolation basin cores, excavations and natural exposures, and an archeological site, constrain relative sea-level change since the last glaciation in the northern Strait of Georgia, British Columbia. Relative sea level fell rapidly from about 150 m elevation to 45 m elevation from 11 750 to 11 000 BP (13 750 to 13 000 cal BP), then its rate of fall slowed. The initial rapid emergence began soon after the transition from proximal to distal glaciomarine sedimentation, when the glacial front retreated from the Strait of Georgia and the Earth’s surface was unloaded. A sea-level lowstand a few metres below present-day sea level may have occurred in the early Holocene, but sea level was near its present level by 2000 BP. Sea-level change in the northern Strait of Georgia lagged the mid Strait of Georgia, 80 km to the south, by a few hundred years during initial emergence. The lowstand in the northern strait was later and probably shallower than in the mid strait. Isostatic depression inferred from the sea-level observations can be fit with two decaying exponential terms with characteristic decay times of 500 and 2600 years. The faster decay time corresponds to a shallow mantle viscosity of about 1019 Pa s, consistent with previous glacio-isostatic modelling. The present-day crustal uplift rate from the residual isostatic effects of the Cordilleran Ice Sheet is about 0.25 mm/a. Crustal uplift is not expected to significantly ameliorate projected sea-level rise in the mid and northern Strait of Georgia because present-day vertical crustal movements are inferred to be small.Vingt-quatre nouvelles dates au 14C provenant de carottes sédimentaires de bassins isolés, d’excavations, de coupes naturellement exposées et archéologiques permettent de cerner les changements du niveau marin relatif depuis la dernière glaciation dans la partie nord du détroit de Géorgie, en Colombie-Britannique. Le niveau marin relatif a rapidement passé de 150 m à 45 m d’altitude entre 11 750 et 11 000 ans BP (13 750-13 000 cal. BP), le taux d’abaissement ayant ralenti par la suite. L’émersion initiale rapide correspond à la fin de la sédimentation glaciomarine distale qui accompagnait le retrait du front glaciaire. Un bas niveau de quelques mètres sous le niveau actuel a pu s’instaurer durant l’Holocène inférieur, jusqu’en 2000 ans BP. Au début, le soulèvement isostatique a accusé un retard de quelques siècle sur celui de la zone du détroit à 80 km plus au sud. Le bas niveau de la partie nord du détroit est survenu plus tard et fut moins prononcé. Les données indiquent un enfoncement isostatique de type exponentiel avec des constantes de désintégration de 500 et de 2600 ans 14C. Le taux le plus rapide correspond à une viscosité du manteau terrestre d’environ 1019 Pa s, ce qui concorde avec les résultats de la modélisation glacio-isostatique. Le taux de soulèvement glacio-isostatique actuel résultant de l’inlandsis de la Cordillère s’établit à environ 0,25 mm/a. Ce taux ne peut contrer les effets du rehaussement du niveau marin prévu pour cette région en raison des faibles mouvements de la croûte terrestre qui y sont envisagés

Influence of transport and ocean ice extent on biogenic aerosol sulfur in the Arctic atmosphere

The recent decline in sea ice cover in the Arctic Ocean could affect the regional radiative forcing via changes in sea ice-atmosphere exchange of dimethyl sulfide (DMS) and biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonic acid (MSA). This study examines relationships between changes in total sea ice extent north of 70 degrees N and atmospheric MSA measurement at Alert, Nunavut, during 1980-2009; at Barrow, Alaska, during 1997-2008; and at Ny-Alesund, Svalbard, for 1991-2004. During the 1980-1989 and 1990-1997 periods, summer (July-August) and June MSA concentrations at Alert decreased. In general, MSA concentrations increased at all locations since 2000 with respect to 1990 values, specifically during June and summer at Alert and in summer at Barrow and Ny-Alesund. Our results show variability in MSA at all sites is related to changes in the source strengths of DMS, possibly linked to changes in sea ice extent as well as to changes in atmospheric transport patterns. Since 2000, a late spring increase in atmospheric MSA at the three sites coincides with the northward migration of the marginal ice edge zone where high DMS emissions from ocean to atmosphere have previously been reported. Significant negative correlations are found between sea ice extent and MSA concentrations at the three sites during the spring and June. These results suggest that a decrease in seasonal ice cover influencing other mechanisms of DMS production could lead to higher atmospheric MSA concentrations